The production of gaseous hydrogen, and particularly, gaseous hydrogen of high purity, is known in the prior art. A variety of feedstocks are known to be useful for these processes, including petroleum, coal, biomass, oil sands, coke, tar, wax oil shales, or combinations of these materials. Depending upon the feedstock selected, the amount of sulfur and halogens present in the feedstock can vary extensively, and many considerations, including catalyst poisoning and the cost of environmental control equipment can be effected by these specific contaminants.
Also, the process used will affect the amount of carbon dioxide produced. As carbon dioxide is associated with global warming, emissions of carbon dioxide must be controlled.
It is therefore an unmet advantage of the prior art to provide a process of this type wherein the carbon dioxide, sulfur and halides are captured as a part of the hydrogen production process.
The rising energy demand coupled with the depleting global oil reserves and the environmental degradation due to emissions has led to extensive research in the field of clean energy production. The total energy use, globally, has been predicted to increase from 421 quadrillion BTU in 2003 to 722 quadrillion BTU in 2030.1 In the United States, the annual energy consumption is projected to increase by 71% from 2003 to 2030, which is much higher than the predicted increase in the domestic energy production. Currently, the United States is dependent on foreign oil for 56% of its energy needs. This translates to the fact that although the production capacity of petroleum products and natural gas will increase, the US will be dependent on foreign oil for 70% of its energy needs by 2025.1 On the other front, the energy related CO2 emission has increased at an annual average percentage of 1.3% in the past decade and is projected by the EIA to increase at the same rate till 2030. To add to this, oil prices are expected to soar up by 50% at the end of 2030.1 Hence, the implementation of energy generation technologies as well as production of “Green” fuels which will reduce the dependence on oil, limit the emissions of CO2, sulfur and other pollutants and be economically feasible are the need of the hour.
This need has led to a global push towards the development of efficient, economical, and reliable carbon capture and sequestration technologies (CCS) for application to fossil fuel based power plants. Coal is present in abundance, about 494 billion tons of reserves in the United States, within which the state of Ohio has 5% or 24 billion tons of reserves. While it gives rise to harmful emissions it can be used to provide a major portion of our energy needs if CCS is implemented in a carbon constrained scenario. The implementation of CO2 capture could be through post combustion capture, oxy-combustion and pre-combustion. These technologies could be applied to either coal, natural gas or biomass based systems. FIG. 1 illustrates these concepts through simplified flow diagrams.
Post combustion capture technology involves the combustion of coal or natural gas to produce hot flue gas which is used to generate steam. The CO2 from the flue gas is then captured using solvents or sorbents. Although coal combustion for power generation is economically viable in a non-carbon constrained scenario, this will not be true when a CO2 regulation is applied. This is because the combustion of coal or natural gas results in the production of large volumes of flue gas in which the CO2 concentration is very low (13-14% for coal combustion and 3-4% for natural gas combustion) and hence the capture of CO2 becomes inefficient and expensive. Addition of CO2 capture results in plant efficiency losses of 8-12% resulting in a net efficiency of 35% for a Super Critical Pulverized Coal Combustion (SC-PCC) plant on an LHV basis.2 In oxy-combustion, the fuel is burnt in oxygen and recycled flue gas, to produce a concentrated stream containing CO2 and H2O which is then dried, compressed and transported for sequestration. Although oxy-combustion obviates the need for a separate CO2 capture stage, it requires an Air Separation Unit (ASU) which is energy intensive and expensive. Oxy-combustion also yields in an overall LHV efficiency of 35% for an SC-PCC plant similar to the post combustion capture case.2 Pre combustion capture involves the gasification of coal or the reforming of natural gas to produce syngas. The syngas is then cleaned and sent to shift reactors (WGSR) to convert the carbon monoxide to H2 and CO2 in the presence of steam. The CO2 is then captured from the shifted syngas and the H2 is either combusted to produce electricity or purified in a Pressure Swing Absorber (PSA) and used for the production of chemicals and liquid fuels. The overall efficiency of an IGCC plant with CO2 capture is 38-40% which is higher than that for post combustion and oxy-combustion systems.2 
Pre-combustion capture technologies are a potential solution to efficient and economical CCS implementation as gasification results in the production of a lower level of criteria pollutants when compared to combustion and the application of CCS to gasification systems is more efficient and economical when compared to CCS for post combustion systems. It has been estimated that with the implementation of CCS using solvent based systems, the increase in the COE for an IGCC is 25 to 40% while that for PC boilers is 60 to 85%. In a carbon constrained scenario, it has been estimated that the cost of a super critical PC boiler will be $2140/KWe while that of an IGCC will be $1890/KWe. In addition to being more economical and efficient, gasification is also very versatile and capable of producing H2 and liquid fuels in addition to electricity.3 
Applying CO2 capture to coal gasification requires the addition of shift reactors, a CO2 separation process and CO2 compression and drying. In a typical gasification system, coal is partially oxidized in the presence of steam and oxygen to produce syngas which is then converted to H2, electricity or liquid fuels.Coal Gasification:CxHy+H2O=xCO+(½+1)H2  (1)
For the implementation of CCS, the CO in syngas needs to be converted to H2 and CO2 via the WGS reaction so that a large fraction of the carbon content can be captured.WGS reaction:CO+H2O=CO2+H2  (2)
In the conventional scenario, a series of shift reactors with catalysts and excess steam addition is used due to the thermodynamic limitation of the WGS reaction. Depending on the sulfur tolerance of the catalyst, the WGSR can be conducted as a raw syngas (sour) shift or the clean syngas (sweet) shift. Commercially the clean WGSR is carried out in two stages: the high and low temperature shift reactors using iron oxide and copper catalysts respectively. The high temperature shift is conducted to convert the bulk of the carbon monoxide to H2 due to the fast kinetics. The lower temperature shift reaction is carried out as the equilibrium conversion is higher at lower temperatures but the gas stream has to be cooled down to 210 C-240 C which makes the process, energy inefficient.4 Further, the commercial iron oxide catalyst has a sulfur tolerance of only about 100 ppm and the copper catalyst has a lower tolerance to sulfur (<0.1 ppm) and chloride impurities. Hence syngas clean up is required upstream of the shift reactors to remove sulfur, chloride and other impurities and downstream of the shift operation to remove CO2. Cleanup is achieved using conventional scrubbing technology which is energy intensive due to the cooling and heating requirements. The sour gas shift uses a sulfided catalyst which is resistant to high sulfur concentrations in the syngas stream and operates at a temperature of 250-500 C. By using the raw gas shift, sulfur removal and CO2 removal can be conducted down stream of the shift reactor in an integrated mode. However the extent of CO conversion is lower in the raw gas shift than in the clean gas shift. Addition of the CO2 capture step results in a 25-40% increase in the cost of electricity (COE), 7.2% decrease in the efficiency, 2.1% due to CO2 compression and 0.9% due to CO2 capture.3 
Conventional pre-combustion capture in a natural gas based plant involves methane reforming which is conducted at temperatures greater than 900 C and is highly energy intensive.5 Steam Methane Reforming(SMR):CH4+H2O=CO+3H2  (3)
The syngas obtained is then shifted similar to the operation in the IGCC system and CO2 capture is achieved at low temperatures using physical (eg. selexol, rectisol, chilled ammonia) or chemical (eg. amine solutions) solvents resulting in a large increase in the parasitic energy requirement and related cost of energy. Hence there is a need to improve the energy efficiency and economics by implementing process intensification to reduce the foot print and improve the heat integration within the system.
The Calcium Looping Process (CLP) developed at the Ohio State University6, as illustrated in FIGS. 2 and 3, improves the efficiency of the coal/natural gas to H2 process by integrating various unit operations into a single stage. The CLP not only aids in curbing CO2 emissions but also improves the efficiency and reduces the CO2 foot print. It utilizes a high temperature regenerable CaO sorbent which in addition to capturing the CO2, enhances the yield of H2 and simultaneously captures sulfur and halide impurities. It also enhances the yield of liquid fuels by reforming the lighter hydrocarbons and unconverted syngas into hydrogen which is used to increase the H2:CO ratio in the syngas to 2 and for hydrotreating the liquid fuel.
FIG. 2 depicts the integration of the CLP in a coal gasification system. Syngas obtained from coal gasification is sent through a particulate capture device to the integrated H2 production reactor. When CaO is injected into the syngas it reacts with the CO2, H2S, COS and HCl to form a mixture containing predominantly CaCO3 and small amounts of calcium sulfide and calcium chloride. The insitu removal of CO2 removes the equilibrium limitation of the WGS reaction thereby obviating the need for a catalyst and excess steam addition. The CaCO3 is subsequently calcined to yield a pure CO2 stream for sequestration and the CaO is recycled back. In this process, naturally occurring limestone which is cheap and abundantly available is used and its capture capacity is maintained at 12.5 moles CO2/Kg of CaO over multiple cycles which is significantly larger than other solvents and sorbents. Thus the CLP integrates several unit operations, such as the WGSR, CO2 capture system, sulfur removal and halide removal in one process module. FIG. 3 shows the integration of the CLP in a natural gas reforming process in which the unit operations namely, reforming, WGS, CO2 capture and sulfur removal are integrated in a single reactor system. Within the H2 production reactor, the natural gas is reformed with steam in the presence of the reforming catalyst and CaO sorbent. The removal of CO2 removes the thermodynamic limitation of the WGSR and the reforming reaction and results in a high conversion of the methane to H2. The H2 production reactor is heat neutral due to the exothermic energy from the WGS and carbonation reactions being equal to the endothermic reforming reaction heat duty. Hence the temperature of operation for the reforming reaction can be reduced from over 900 C to 650 C. The spent sorbent containing CaCO3, CaO and CaS is separated from the H2 and regenerated in a calciner to produce a sequestration ready CO2 stream. The CaO sorbent is then recycled back to the integrated H2 production reactor.
The overall objectives of the CLP are to improve process efficiency and economics by process intensification, produce H2 for electricity generation, chemicals and liquid fuels synthesis with integrated carbon and contaminants capture at high temperatures, produce a sequestration ready CO2 stream, reduce excess steam requirement and obviate the need for a WGS catalyst. Experimental investigation in a bench scale facility reveals that high purity H2 of 99.7% purity with less that 1 ppm sulfur impurity can be produced. Process evaluation using ASPEN Plus® software suggests that the overall efficiency of the coal to H2 process integrated with the CLP is 64% (HHV) which is significantly higher than 57% (HHV) achieved by the state-of-the-art H2 from coal process.
This and other unmet advantages are provided by the device and method described and shown in more detail below.